JP3136664B2 - Magnetic recording medium and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, magnetic recording media have been used in disk drive devices. When manufacturing such a disk, an intermediate layer, a magnetic layer, and a protective layer are usually formed on a nonmagnetic substrate by using a sputtering method.

Hereinafter, a conventional method for manufacturing a magnetic recording medium and a magnetic recording medium obtained by the method will be described.

It is known that gas components in a sputtering atmosphere take in impurity gas in addition to argon gas used as a sputtering gas. In particular, oxygen (O ₂ ) as this impurity gas is taken into the intermediate layer or the magnetic layer together with sputtered particles when sputtering the intermediate layer or the magnetic layer, causing an oxidation reaction of the metal. The oxide of this metal significantly degrades the magnetic properties. The oxygen or the like is mainly supplied as a gas released from the carrier, a gas released from the wall of the sputtering chamber, or moisture in a gas component brought in from outside during the transport of the carrier. The supplied water is decomposed into hydrogen and oxygen in the plasma during sputtering, and activated oxygen is mainly taken into sputtered particles.

In recent years, a bias sputtering method has been used to obtain a stable and high coercive force. Particularly, in the bias sputtering method, an impurity gas concentration is increased, and in order to obtain good magnetic characteristics, an oxygen component is required. It is essential to control the pressure.

[0006]

However, in the above-mentioned conventional structure, the influence of oxygen cannot be avoided. Particularly, when the oxygen partial pressure is high, a magnetic recording medium having a stable and high coercive force cannot be obtained. The distribution of the coercive force between the media and within the magnetic recording medium becomes large, and the quality is degraded, the yield is poor, and the productivity is remarkably reduced.

The present invention solves the above-mentioned conventional problems. By manufacturing a magnetic recording medium using a sputtering method, by controlling the oxygen partial pressure to be low when forming an intermediate layer and a magnetic layer, it is possible to reduce the oxygen partial pressure. It is an object of the present invention to provide a high quality magnetic recording medium having a high coercive force, and to provide a method of manufacturing a magnetic recording medium capable of mass-producing a magnetic recording medium having a high coercive force and a stable quality at a high yield.

[0008]

In order to achieve the above object, a magnetic recording medium according to the present invention is a magnetic recording medium comprising a non-magnetic substrate on which an intermediate layer, a magnetic layer and the like are formed. And / or the magnetic layer is formed under a hydrogen partial pressure of 2 × 10 ⁻⁵ Pa. The method for manufacturing a magnetic recording medium is such that an intermediate layer, a magnetic layer, and the like are formed on a non-magnetic substrate by sputtering. A method for producing a magnetic recording medium on which a film is formed, wherein at least a temperature in a system of a heating chamber and a film forming chamber of an intermediate layer / magnetic layer is set to 35 ° C.
To 100 ° C., preferably 40 ° C. to 70 ° C., and a hydrogen gas partial pressure of 2.5 × 10 ⁻⁵ Pa or less, preferably 2 × 1
0 ^-5 Pa consisting configuration for performing controls below.

Here, Co or the like or an alloy thereof is desirable for the magnetic layer from the viewpoint of quality and the like.

[0010]

With this configuration, at least the inside of the system of the heating chamber and the film forming chamber for the intermediate layer and the magnetic layer of the sputtering apparatus is kept at 35 ° C.
By heating to 100 ° C., preferably 40 ° C. to 70 ° C., impurity gas brought into the system during each unit operation,
In particular, the partial pressure of water is reduced, the oxidation reaction of the metal due to oxygen content is suppressed, and a magnetic recording medium having a stable high coercive force and squareness ratio can be obtained with a high yield.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an in-line type sputtering apparatus used in a method for manufacturing a magnetic recording medium according to an embodiment of the present invention. 1 is a disk carrier on which a magnetic recording medium is mounted, 2 is a non-magnetic substrate made of aluminum alloy, glass or the like, 3 is a first heating chamber for releasing impurity gas contained in the carrier, and 4 is a film forming chamber. A second heating chamber 5 for controlling the substrate temperature, 5 is a film forming chamber for continuously forming an intermediate layer made of a chromium alloy or the like and a magnetic layer of cobalt or its alloy by a sputtering method, and 6 is a variety of gases. , A protective layer film forming chamber for forming a protective layer such as a lubricating film by sputtering or CVD, 8 a transfer chamber, 9 a vacuum exhaust system for evacuating each chamber, Reference numeral 10 denotes a gate valve connecting each chamber, 11 denotes a gas analyzer, 12 denotes an exhaust system for evacuating the gas analysis tube, 13 denotes at least a heating chamber, and each chamber of an intermediate layer / magnetic layer deposition chamber. With hot water or a heater at 35 ° C to 100 ° C, preferably 4 ° C. ℃ ~70 ℃
, A flow controller 14 for an Ar gas introduced as a sputtering gas, 15 a valve for adjusting a flow rate of an Ar gas, and 16 a mounting portion 17 for the disk carrier 1.
This is a transport system for moving the outer periphery 18 at a constant speed.
The entire process of each unit operation may be heated at the above temperature in addition to the heating chamber and the chamber for forming the intermediate layer and the magnetic layer. This is to completely suppress the adsorption of moisture to the disk carrier or the like.

A method for manufacturing a magnetic recording medium according to the present invention and a magnetic recording medium obtained by the method will be described below using the sputtering apparatus configured as described above. FIG. 2 shows a temporal change required until the transfer chamber 8 reaches a vacuum when the heating is always performed at a temperature of 40 ° C. to 70 ° C. even during maintenance of the sputtering apparatus which is one embodiment of the manufacturing method of the present invention. FIG. As is clear from FIG. 2, 6 × 10 ⁻⁵ T
In this embodiment, the evacuation time (sec) required for the number of deposition carriers is 89 seconds when the number of film forming carriers is zero, and 91 seconds when the number of film formation carriers is 1,000. there were. On the other hand, in the conventional example, 97 seconds are required when the number of deposition carriers is 0, and 105 seconds is required when the number of deposition carriers is 1000. The evacuation time is remarkably increased as the number of deposition carriers is increased. This is because the gas brought in by the carrier transport, mainly moisture, adheres to the inner wall of the transport chamber 8 and the accompanying moisture increases as the number of carriers increases, and the evacuation speed decreases accordingly. The effect of the moisture is also detected by a gas analyzer provided in the sputtering chamber 5. In the case of the conventional example, the tendency of the hydrogen gas partial pressure to increase with the number of deposition carriers is remarkable. Was.

Next, the relationship between the partial pressure of hydrogen gas and the coercive force was examined while maintaining the temperature in the system at 50 ° C. to 60 ° C. under the manufacturing conditions of this embodiment. FIG. 3 is a diagram showing the relationship between the hydrogen gas partial pressure and the coercive force. Although the partial pressure of hydrogen gas as is clear from FIG. 3 can be manufactured a magnetic recording medium having a high coercive force of more than 1500 Oe in the following ^{2 × 10 -5 Pa, 2 ×} 10 -5 Pa to exceed the coercive force is rapidly At 2.7 × 10 ⁻⁵ Pa, the coercive force had a coercive force of not more than 1400 Oersted, and variations in magnetic properties were observed between the magnetic recording media and in each part of the magnetic recording media.

Incidentally, a Co alloy layer was particularly used as the magnetic layer. This is because the quality is stable among magnetic materials widely used in application media and the like.

[0016] From this, the temperature in the system is 50 ° C ~ 60 ° C
It was found that, when the hydrogen gas partial pressure was kept at least 2 × 10 ⁻⁵ Pa or less, a magnetic recording medium with high coercive force and stable quality could be obtained at a high yield. Maintaining the temperature in the system and the low hydrogen partial pressure is selected from the viewpoint of commercial economy according to the size of the sputtering apparatus.

[0017]

As described above, according to the present invention, when the intermediate layer and the magnetic layer are formed by the sputtering method and the magnetic recording medium is manufactured, in particular, by controlling the oxygen partial pressure, the quality is stabilized. It is possible to provide a magnetic recording medium having an improved squareness ratio with a high coercive force, and to realize a method of manufacturing an excellent magnetic recording medium capable of mass-producing such an excellent magnetic recording medium at a high yield and at low cost. Things.

[Brief description of the drawings]

FIG. 1 is a schematic view of an in-line type sputtering apparatus which is one means of a method for manufacturing a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change with time until a vacuum is reached;

FIG. 3 is a diagram showing the dependence of coercive force on hydrogen partial pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc carrier 2 Nonmagnetic substrate 3 First heating chamber 4 Second heating chamber 5 Intermediate layer and magnetic layer deposition chamber 6 Isolation chamber 7 Protective layer deposition chamber 8 Transfer chamber 9 Vacuum exhaust system 10 Gate valve 11 Gas analyzer 12 Vacuum exhaust system for gas analysis tube 13 Heating system 14 Ar gas flow controller 15 Flow control valve 16 Transport system 17 Disk mounting position 18 Disk removal position

Claims (2)

(57) [Claims] 1. A magnetic recording medium comprising an intermediate layer, a magnetic layer and the like formed on a non-magnetic substrate, wherein the intermediate layer and / or the magnetic layer is formed under a hydrogen partial pressure of 2 × 10 ^-5 Pa. A magnetic recording medium characterized by being recorded. 2. A method of manufacturing a magnetic recording medium comprising forming an intermediate layer, a magnetic layer, and the like on a non-magnetic substrate by a sputtering method, comprising: And the temperature in the system is 35 ° C to 10 ° C.
0 ° C., preferably 40 ° C. to 70 ° C., and a hydrogen gas partial pressure of 2.5 × 10 ⁻⁵ Pa or less, preferably 2 × 10 ⁻⁵ P
a. A method for manufacturing a magnetic recording medium, wherein the method is performed under the following conditions.